sudo apt-get --purge remove postgresql
sudo apt-get purge postgresql*
sudo apt-get --purge remove postgresql postgresql-doc postgresql-commonsudo apt-get --purge remove postgresql postgresql-doc postgresql-common
sudo apt-get --purge remove postgresqlsudo aptitude purge postgresql postgresql-common
sudo dpkg -P postgresql-8.4
sudo find / -name postgresql -exec rm -Rf {} \;
sudo find / -name pgsql -exec rm -Rf {} \;
sudo find / -name psql -exec rm -Rf {} \;
sudo userdel postgres